Pressurized conduits or pipes convey fluids, both liquid and gas, in municipalities, industrial plants and commercial installations. When originally installed, a network of pipes may include isolation valves used to block or otherwise isolate certain sections of the pipe for repairs, relocation or installation of new components into the pipe. For example, when a shutdown is required in a municipal water system, a significant portion of a supply area may be deprived of water service. Accordingly, in addition to the inconvenience to residents, schools, hospitals, commercial and/or industrial facilities may have to be shut down until water service is restored.
When a network of pipes is in need of repair maintenance crews make every attempt to perform the repairs quickly and with minimal service interruption. However, many municipalities, industrial plants and other commercial installations have incomplete, outdated or inaccurate records for the network of pipes which make it difficult to determine certain pipe characteristics such as but not limited to, size, material, class or other such specification. Exposing the outside of a pipe in need of repair can provide information related to pipe material and pipe outer diameter. However, determination of pipe class and internal pipe geometry may require use of expensive pipe imaging and gauging equipment (e.g., ultrasonic, radiation or other such imaging technology), drilling and tapping multiple holes in the pipe or even removing an entire section of pipe for closer inspection.
Therefore, maintenance crews have a need for alternative technology that provides an efficient and reliable method for determining internal pipe geometries such as but not limited to, wall thickness and internal diameter in order to select the proper tools and replacement parts to carry out pipe network repairs. As a result, equipment which cuts two taps into a single pipe location (e.g., a core sample and a secondary tap) can reduce repair costs, reduce pipe network downtime, and help maintain overall integrity of the pipe.
A hole saw including a pilot drill is disclosed in U.S. Pat. No. 7,357,605 (hereinafter the “'605 patent”), entitled, “Pilot Drill with Coupon Retainer and Hot Tapping Machine Using the same.” The tapping device of the '605 patent includes a hand drill to turn a shaft having a hole saw at the inner end thereof to drill a hole and provide a new tap in the pressurized main. The pilot drill has cutting blades and a hole formed through the drill. The hole includes a wire disposed there through and when the pilot drill penetrates the wall of the main the wire ends may sling outward serving as a coupon retaining finger or arms. However, the tapping device of the '605 patent does not first provide a core cutter which may retrieve a core sample to determine unknown characteristics of the main and subsequently provide a size-on-size cutter to form the new tap in the main. Furthermore, the tapping device of the '605 patent is not interchangeable for particular application needs.
Accordingly, improved core sampling and tapping assemblies that may be installed in pressurized pipes and conduits to sample the pipe prior to tapping are needed.